Wi-Fi, also known as WLAN (Wireless Local Area Network), is standardized by IEEE (Institute of Electrical and Electronics Engineers) in the 802.11 specifications (IEEE Standard for Information technology—Tele-communications and information exchange between systems. Local and metropolitan area networks—Specific requirements. Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications). The terms Wi-Fi and WLAN will be used interchangeably throughout this document. Wi-Fi is a technology that currently mainly operates on the 2.4 GHz or the 5 GHz band. The IEEE 802.11 specifications regulate the STA (STAtion, i.e. access points or wireless terminals) physical layer, MAC layer and other aspects to secure compatibility and inter-operability between access points and portable terminals, which herein will be referred to as wireless devices or user equipment, UEs. Wi-Fi is generally operated in unlicensed bands, and as such, communication over Wi-Fi may be subject to interference sources from any number of both known and unknown devices. Wi-Fi is commonly used as wireless extensions to fixed broadband access, e.g., in domestic environments and hotspots, like airports, train stations and restaurants.
Recently, Wi-Fi has been subject to increased interest from cellular network operators, not only as an extension to fixed broadband access. The interest is mainly about using the Wi-Fi technology as an extension, or alternative, to cellular radio access network technologies to handle the ever increasing wireless bandwidth demands. Cellular operators that are currently serving mobile users with, e.g., any of the 3GPP technologies, LTE, UMTS/WCDMA, or GSM, consider Wi-Fi as a wireless technology that can provide good support in their regular cellular networks. The term “operator-controlled Wi-Fi” refers to a Wi-Fi deployment that on some level is integrated with a cellular network operator's existing network, and where the 3GPP radio access networks and the Wi-Fi wireless access may even be connected to the same core network and provide the same services.
There is currently quite intense activity in the area of operator-controlled Wi-Fi in several standardization organizations. In 3GPP, activities to connect Wi-Fi access points to the 3GPP-specified core network is pursued, and in Wi-Fi alliance (WFA), activities related to certification of Wi-Fi products are undertaken, which to some extent also is driven by the need to make Wi-Fi a viable wireless technology for cellular operators to support high bandwidth offerings in their networks. The term ‘Wi-Fi offload’ is commonly used and refers to that cellular network operators seek means to offload traffic from their cellular networks to Wi-Fi, e.g., in peak-traffic-hours and in situations when the cellular network for one reason or another needs to be off-loaded, e.g., to provide requested quality of service, maximize bandwidth or simply to ensure coverage.
When considering steering traffic from LTE to Wi-Fi as a way to improve user experience, one of the most important QoS indicators for most data services is the user throughput. Thus, in order to decide if user traffic should be steered from a current serving RAT or network to another, the user throughput in the other RAT or network needs to be evaluated. Since the evaluation needs to be performed before any data is actually transferred in the other RAT, very limited knowledge can be assumed as being the input to traffic steering functions.
User throughput prediction in a Wi-Fi system has been previously studied. In such studies, the predicted Wi-Fi throughput is estimated based on cell level statistics including served traffic, average traffic load, the number of currently connected users and/or packet transmission statistics as well as limited UE specific knowledge, e.g. a measured signal strength. As a contention based system, the DL and UL traffic in a WLAN cell will compete for the channel access. And nodes in one cell may compete for the channel access with nodes in neighbor cells operating on the same channel as well. These factors should be considered in the throughput estimation.
In order to optimize user experience in a multi-radio access technology (RAT) environment, the RAT or network that provides the highest user throughput should be selected to serve the user, given that throughput is identified as very important for user experience. User throughput prediction is a critical component for this optimization. However, it's a challenging task to predict user throughput, especially when input information is limited, which is the case when the user has not been connected to the network yet.
In other words, it is very important to predict the throughput in a wireless communication network, e.g. in order to evaluate whether to steer user traffic to a WLAN from an LTE system while maintaining a high user satisfaction. However, it is identified as a problem how to predict such a throughput in a satisfying manner.